1. Field of the Invention
The present invention relates to a Schottky barrier tunnel transistor using a Schottky tunnel barrier naturally formed at a semiconductor-metal junction as a tunnel barrier, and a method of manufacturing the same. More particularly, the present invention relates to a method of manufacturing a Schottky barrier tunnel transistor capable of minimizing leakage current caused by damage to a gate sidewall, which is useful in manufacturing a Schottky barrier tunnel transistor using samarium silicide.
2. Discussion of Related Art
Recent semiconductor device manufacturing technology enables the manufacture of a transistor having a short channel of 50 nm or less. However, reduction of the size of a device is accompanied by new phenomena which adversely affect the operation characteristics of the device. Specifically, in a transistor having a short channel of 100 nm or less, leakage current caused by a short channel effect is very large and thus important to suitably control. A variety of research for overcoming such drawbacks is underway. One new alternative being examined is the reduction of a Schottky MOSFET in which a source and drain are replaced by metal or silicide to have a channel length of 35 mm or less. As junction depth is reduced, a parasitic resistance component of the source and drain including a source-drain extension (SDE) caused by conventional ion diffusion is increased so that, assuming a doping concentration of 1E19/cm3 and a depth of 10 nm, a surface resistance value exceeds 500 ohm/sq.
FIG. 1 is a cross-sectional view of a conventional widely used Schottky barrier tunnel transistor. In the conventional technology for manufacturing the Schottky barrier tunnel transistor, a gate electrode 21 was first formed and a silicidation process of a source and a drain was finally performed. However, in an N-type Schottky barrier tunnel transistor, metal having very strong reactivity is deposited on the source and drain and then the resultant is annealed. Accordingly, gate leakage current is generated through an insulating layer 28 formed on a gate sidewall. In other words, in the conventional method of manufacturing the Schottky barrier tunnel transistor, there is a drawback in that, in the N-type transistor, the metal deposited on the source and drain damages the insulating layer 28 formed on the gate sidewall due to its very large reactivity, thereby causing the gate leakage current.
In order to prevent the above-described drawback side effect, in the conventional transistor manufacturing method, after the silicidation process is performed, a metal layer generated from the gate sidewall insulating layer 28 should be removed. The removal of the metal layer actually has many difficulties. As a result, it is difficult to suppress generation of the gate leakage current caused by the damage to the gate sidewall insulating layer 28.